SB2026061994 - Multiple vulnerabilities in Confluence Data Center

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Main Vulnerability Database SB2026061994

SB2026061994 - Multiple vulnerabilities in Confluence Data Center

Published: June 19, 2026 Updated: June 23, 2026

Security Bulletin ID SB2026061994
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 14
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 86% Low 14%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 14 vulnerabilities.


1) Inefficient Algorithmic Complexity (CVE-ID: CVE-2026-27903)

CWE-ID: CWE-407 - Inefficient Algorithmic Complexity

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to inefficient algorithmic complexity in matchOne() when processing glob patterns containing multiple non-adjacent GLOBSTAR segments. A remote attacker can supply a specially crafted glob pattern to cause a denial of service.

The issue is triggered on non-matching input and can stall the Node.js event loop while the recursive call tree is fully explored.


2) Inefficient regular expression complexity (CVE-ID: CVE-2026-26996)

CWE-ID: CWE-1333 - Inefficient Regular Expression Complexity

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient input validation when processing untrusted input with a regular expressions within "minimatch" function. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.


3) Improper access control (CVE-ID: CVE-2026-43515)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Green


The vulnerability allows a remote attacker to bypass security constraints.

The vulnerability exists due to improper access control in HTTP method constraint processing when evaluating multiple security constraints for the same extension pattern. A remote attacker can send a request using an improperly constrained HTTP method to bypass security constraints.


4) Input validation error (CVE-ID: CVE-2026-41293)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to trigger unexpected application behavior.

The vulnerability exists due to improper input validation in HTTP/2 request header handling when exposing header values through the Servlet API. A remote attacker can send crafted HTTP/2 request headers to trigger unexpected application behavior.

This may affect applications that assume header values exposed through the Servlet API are specification compliant.


5) Improper Authentication (CVE-ID: CVE-2026-43512)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Green


The vulnerability allows a remote attacker to authenticate as an unknown user.

The vulnerability exists due to improper authentication in the DIGEST authenticator when processing authentication for users not known to the configured Realm. A remote attacker can submit the password "null" for an unknown user to authenticate as an unknown user.

This occurs only when DIGEST authentication is configured.


6) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2026-42584)

CWE-ID: CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to disrupt HTTP parsing integrity and availability on the connection.

The vulnerability exists due to inconsistent interpretation of HTTP responses in HttpClientCodec when processing pipelined HTTP/1.1 responses that include a 1xx response before a GET response body and a subsequent HEAD response. A remote attacker can send a specially crafted sequence of HTTP responses to disrupt HTTP parsing integrity and availability on the connection.

Exploitation requires HTTP/1.1 pipelining, a HEAD request in the pipeline, and a server response sequence that includes a 1xx response.


7) Resource exhaustion (CVE-ID: CVE-2026-41284)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in WebDAV LOCK and PROPFIND handling when processing request bodies. A remote attacker can send a large request body to cause a denial of service.

The affected requests are available to unauthenticated users.


8) Improper Handling of Case Sensitivity (CVE-ID: CVE-2026-43513)

CWE-ID: CWE-178 - Improper Handling of Case Sensitivity

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to weaken brute-force protection against a user's password.

The vulnerability exists due to improper input handling in LockOutRealm when processing case-insensitive user names. A remote attacker can vary the case of a user name during authentication attempts to weaken brute-force protection against a user's password.

This affects Realms where user names are treated as case insensitive.


9) Null Byte Interaction Error (Poison Null Byte) (CVE-ID: CVE-2026-42579)

CWE-ID: CWE-626 - Null Byte Interaction Error (Poison Null Byte)

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to bypass domain validation and poison DNS caches.

The vulnerability exists due to improper input validation in io.netty.handler.codec.dns.DnsCodecUtil encodeDomainName() when encoding user-influenced domain names. A remote attacker can supply a crafted domain name containing null bytes, overlength labels, or empty labels to bypass domain validation and poison DNS caches.

The issue affects the encoder path and relies on applications using user-influenced hostnames to construct DNS queries.


10) Inefficient regular expression complexity (CVE-ID: CVE-2026-27904)

CWE-ID: CWE-1333 - Inefficient Regular Expression Complexity

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient input validation when processing untrusted input with a regular expressions. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.


11) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2026-42585)

CWE-ID: CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to inject arbitrary HTTP requests.

The vulnerability exists due to inconsistent interpretation of HTTP requests in HttpRequestDecoder when parsing malformed Transfer-Encoding headers. A remote attacker can send a specially crafted HTTP request with a malformed "Transfer-Encoding: chunked, identity" header to inject arbitrary HTTP requests.

Exploitation is possible in deployments where a proxy forwards such malformed requests to Netty instead of rejecting them.


12) Resource exhaustion (CVE-ID: CVE-2026-45149)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper resource consumption in the numeric range expansion logic when processing a string containing a single large numeric range. A remote attacker can supply a specially crafted expansion string to cause a denial of service.

User interaction is required to process the crafted expansion input.


13) Resource exhaustion (CVE-ID: CVE-2026-42587)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in HttpContentDecompressor and DelegatingDecompressorFrameListener when processing compressed HTTP request bodies with Content-Encoding set to br, zstd, or snappy. A remote attacker can send a specially crafted compressed payload to cause a denial of service.

The configured maxAllocation limit is enforced for gzip and deflate, but is silently ignored for brotli, zstd, and snappy. The issue affects both HTTP/1.1 and HTTP/2 handling.


14) Information disclosure (CVE-ID: CVE-2026-42498)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote user to disclose authentication headers to a redirect target host.

The vulnerability exists due to exposure of sensitive information in Tomcat's WebSocket client when following a redirected WebSocket request after authentication. A remote user can trigger a redirect after authentication to disclose authentication headers to a redirect target host.

The issue occurs only if a WebSocket request is redirected after authentication.


Remediation

Install update from vendor's website.

References